geckonz08

I am sure plenty of you will be able to advise whether I need oil restrictors to just the main bearings or also in the lifter oil holes ??
The vehicle is a toro with windage trays n large toro sump.
Thankyou in advance .
mike

joe_padavano

Though easy to install, the main bearing restrictors don't really do much. Olds engines route the oil from the pump to the main galleries first. This feeds the lifters and then the valvetrain. The remaining oil feeds the mains, followed by the cam bearings last. Lifter restrictors are more important than the main bearing restrictors, though you can also use restricted pushrods. As for the main restrictors, a zero cost way to accomplish this is to simply drill new, smaller holes in the cam bearings and install them with these new holes aligned with the feed holes. Same result without the cost of restrictors.

88 coupe

With hydraulic lifters, they would be the logical choice as, the lifters need oil pressure and volume to operate efficiently, and solids only need lubrication.

Pipe cleaners inside the pushrods are simple, cheap, efficient, and have been used since the 1950s. Its just not likely, you'll catch anyone (except me) that will cop to it.

Either method is a waste of time, as they probably don't restrict flow any more than the existing cam bearing clearances.

Most important, is to size the crank clearances to insure adequate flow from the crank, back to the pan.

Norm

380 Racer

I have always used main restrictors, have never had a problem and cheap insurance. Use restricted pushrods. I have seen the pipe cleaner trick used, but after a while you wonder where the fuzzies went off that wire?

geckonz08

thanks guys for that .Think I will go the restricted pushrod way and make sure the mains have good clearances as my first options --not confident to use your pipe cleaners Norm --although cheap I might leave em at the tobacconist tjhis time
thanks
mike

88 coupe

I've never expected that anyone would. It's more Historical Trivia, than advice.

Norm

Run to Rund

The pipe cleaners get pushed up through the oil hole at the top of the pushrod, and chewed off by the oil hole in the tip of the rocker. Use pushrods such as Comp or Smith with small holes, or if you are using adjustable pushrods, you can fit wooden dowels into them with the ends cut at an angle so they can't block the hole.

Oldsguy

And the purpose of all this, or any of this effort is?

88 coupe

Now, there is a rebuttal that actually makes sense.

Norm

geckonz08

As for the main restrictors, a zero cost way to accomplish this is to simply drill new, smaller holes in the cam bearings and install them with these new holes aligned with the feed holes. Same result without the cost of restrictors.[/quote]


So, Joe ,if I read this correctly,by drilling smaller holes I may not have to employ any other works to achieve the result of ensuring there is plenty of oil to the bottom end ?
Have also heard a little about enlarging/porting the return holes in the valley ?? true ??

cheers mike

joe_padavano

So, Joe ,if I read this correctly,by drilling smaller holes I may not have to employ any other works to achieve the result of ensuring there is plenty of oil to the bottom end ?
Have also heard a little about enlarging/porting the return holes in the valley ?? true ??

cheers mike[/QUOTE]

Well, this doesn't solve the lifter bore restrictor problem (which is the higher priority), it just saves a few bucks over the main restrictors. Deburring the drainback paths inside the block is always a good idea.

geckonz08

Dan,The purpose is to try to ensure adequate oil to the bottom end .
You don`t agree with this ?? or think it unnecessary ??

mike

Oldsguy

I really am not sure Mike. There seems to be so much conflict when this subject arises. I do understand if a person is racing an Oldsmobile engine, running it to the upper limits of the rpm range, really stressing the engine that any small amount of machine work while the block is opened up is worth the effort and cheap insurance. But I just can't accept that nasty generalization that Oldsmobiles have poor oiling and grenade due to that short-coming. I just haven't seen many stock or near stock rebuilds that have had this happen. I guess my inquiry did sound sort of smart aleck. Sorry.

geckonz08

not smart alec at all--Iam here to learn about olds engines and to me all opinion is good opinion.Let`s say that without this site ,I would have very little to no chance of re-assembling my 425. The guys where I live(including engine reconditioners I have spoken to ) have very limited olds knowledge.--and admit it.
Thanks for your opinion
mike

88 coupe

Factory oiling system already does that. If a problem shows up, it will be when it gets there.

There must be enough clearance (and resulting oil flow) to cool the bearings, carry away any accumulated residue/deposits, and speed its return to the reservoir.

The degree of modification needed, depends on the actual application. A "production" 455, that seldom goes over 4500 RPM will be perfectly happy with "production" clearances. A 600 HP 455 that often sees 6500 RPM, or more, will need more.

And again, common sense prevails over internet myth.

Norm

Run to Rund

Today's Melling high vol oil pump with bolt on bigger diameter pickup seems to help over the older bandaids with old pumps that didn't seem to flow as much. Of course, a big sump helps because if you suck it dry, your bearings will be toast. I like 7-8 qt sumps if 6000 rpm and racing are contemplated. If you run hydraulics, hopefully you buy ones designed to meter less oil meaning they are for Olds not chevy. With solids, most of them meter too much oil and because they really don't need internal oiling to function, you can drill each oil feed to .136", tap 8-32 (carefully so you don't break a tap), and install restrictors. I made restrictors out of allen set screws that I detempered from their as-supplied extreme hardness by heating red hot and letting them cool naturally. Then I drilled an .040" hole in the center of each. Secure them with red high temp loctite and don't plan on ever removing them.

71 delta88guy

I'm sure many will reply otherwise but..... Oil mods are really not needed UNLESS running the engine at high rpm's sustained. I believe these mods were designed for boat engines that failed due to the oil system limitations.It's unlikely we car guys are going to rev our engines 4,4500,5000 for long periods. Having a 7 qt oil pan might not be a bad idea running a hi volume oil pump but other than that just clean up the junk around the oil returns and run it.

Run to Rund

#3 and #6 rod bearing oil feed drilled holes come to the journals at the wrong angle. At a certain rpm vs. oil pressure vs. stroke the oil is no longer able to get out and those are the rods that spin the bearings. For decades the "fixes" to that and other oiling issues resulting from the large diameter bearings have been to put a heavy chamfer on all oil holes in the crank, and run a 3/8" or so long trough in the crank journal from the hole in the direction the hole "should have been". I have been told the drilled angle was "fixed" in 1971 but haven't verified it.

geckonz08

r to r --the 3 and 6 bearing reference you made is very interesting.When I pulled the engine down it was the #6 rod bearing that had seized --all others were fine

Re previous responses,as my application will be a 'mild street 'application with very little over 4500 stuff ,your help has been great .Thankyou
mike

380 Racer

If you don't want to restrict anything, Just go by the old addage .001 clearence per inch (ie 3" main = .003") and a good oil pump.